Money on counter, type of table? (5,8)

I believe the answer is:

ready reckoner

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'table?' is the definition.
(I've seen this before)

'money on counter type' is the wordplay.
'money' becomes 'ready' (ready can informally mean cash).
'on counter type' becomes 'reckoner' (I can't explain this - if you can you should believe this answer much more).
'ready'+'reckoner'='READY RECKONER'

'of' acts as a link.

Can you help me to learn more?

(Other definitions for ready reckoner that I've seen before include "table" , "I've done your sums for you" , "Book of calculation aids" , "Tables of standard numerical calculations" , "Printed tables used in standard computations" .)

I've seen this clue in The Guardian.

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